Rotary compressor



March 12, 1963 O J. s. MICHIE ROTARY COMPRESSOR Filed Feb. 2, 1959 '7 Sheets-Sheet l FIG] "INVENTOR. JOHN SMITH MlCHlE BY $4M 14 w r TORNEYS March 12, 1963 J. s. MlCHlE 3,081,022

ROTARY COMPRESSOR Filed Feb. 2. 1959 7 Sheets-Sheet 2 I08 m 21 202 z 36 34 '109 84 42 INVENTOR.

JOHN SMITH MICHIE ATTORNEYS March 12, 1963 J. s. MICHIE I 3,081,022

ROTARY COMPRESSOR Filed Feb. 2, 1959 7 Sheets-Sheet a INVENTOR. JOHN SMITH MICHIE ATTRNEYS March 12, 1963 J. s. MlCHIE 3,081,022

ROTARY COMPRESSOR Filed Feb. 2, 1959 7 SheetsSheet 4 INVENTOR. JOHN SMITH MICHI E drw ATTO RNEYS March 12, 1963 J. s. MICHIE 3,0s1,o22

ROTARY COMPRESSOR Filed Feb. 2, 1959 7 Sheets-Sheet 5 FIG]! INVENTOR. JOHN SMITH MICHIE W i/r% March 12, 1963 J. s. MICHIE ROTARY COMPRESSOR 7 Sheets- Sheet 6 Filed Feb. 2, 1959 INVENTOR. JOHN SMITH MICHIE ATTO NEYS XUI ik Hail FIG. I3

March 12, 1963 J. 5. Ml CHlE 3,081,022

ROTARY COMPRESSOR Filed Feb. 2, 1959 7 Sheets-Sheet 7 FIG. 15

INVENTOR. JOHN SMITH MICHI E TTO RNEYS United States Patent Ofitice 3,081 ,022 Patented Mar. 12, 1963 3,081,022 RUTARY COMPRESSOR John Smith Michie, Springfield, Ohio; Amanda Ann Michie, executrix of said John Smith Michie, deceased, assignor to herself, Springfield, Ohio Filed Feb. 2, 1959, Ser. No. 790,616 4- Claims. (Cl. 230-147) The present invention relates to improvements in pumps and compressors of the offset rotor pivoted vane type.

This type of pump includes a casing with a cylindrical pump chamber and a rotary piston within the pump chamber. An inlet port leads into the side of the pump chamber and a discharge port leads from the pump chamber adjacent the inlet port. The ports are separated by a pivoted vane which slides within an axial slot in the piston, and sealingly engages the wall of the chamber between the ports. The piston is eccentrically journalled on a drive shaft which moves the piston in an oscillating path around the edge of the pump chamber to force fluid from the inlet port to the outlet port. I An object of the present invention is to provide an improved offset rotor pivoted vane compressor pump which provides improved sealing surfaces between the piston rotor and the Walls of the pump chamber, and between the vane and the wall of the pump chamber.

Another object of the invention is to provide an improved pump of this type wherein the wear between the piston and chamber walls between the vane and the piston and between the vane and the chamber wall is considerably reduced to increase the operating life and reliability of the pump.

Another object of the invention is to provide an improved pump of the type referred to wherein the permissible manufacturing tolerances are improved, thereby reducing the cost of construction and improving the efliciency and operating characteristics of the pump.

A still further object of the invention is to provide an improved ofiset rotor pivoted vane pump with improved discharge characteristics and higher operating efficiency obtained through unique pump discharge outlet port arrangements and improved piston rotor structures.

A still further object of the invention is to provide an improved lubricating arrangement for an offset rotor pivotedvane pump.

A further object of the invention is to provide a pump capable of compressing gases mixed with lubricant with improved means for separating the lubricant from the gas, and provided with improved means for recirculating lubricant and providing improved lubrication for the pump parts.

A still further object of the invention is to provide an offset rotor pivoted vane pump with improved principles of construction well adapted to use in providing multiple stage pumps.

A more particular object of the invention is to provide an improved vane structure for an offset rotor pivoted vane pump to obtain a longer wear, simplified structure, and improved sealing ability.

Another particular object of the invention is to provide an improved rotor structure for an offset rotor pivoted vane pump with improved features of reliability, wear, and improved sealing relationship with mating arts.

p Other objects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the specification, claims and drawings, in which: 7

FIGURE 1 is a sectional view taken through the axis of an oiiset rotor pivoted vane compressor pump embodying the principles of the present invention;

FIGURE 2 is a vertical sectional view taken substantially along line IIII of FIGURE 1;

FIGURE 3 is a fragmentary sectional view of a por= tion of FIGURE 2 illustrating the relative action of the parts during the discharge of the pump;

FIGURE 3a is a fragmentary sectional View illustrat= ing a modified form of a vane;

FIGURE 4 is another fragmentary sectional view illustratiiig a form of the discharge or outlet ports;

FIGURE 5 is another fragmentary sectional view illus' trating still another form of outlet ports;

FIGURE 6 is a detailed elevational view taken substantially along line VIVI of FIGURE 1, and illus"- trating the lubricant separator flinger;

FIGURE 7 is a detailed elevational view of one form of a sliding separator vane;

FIGURE 8 is a bottom plan view of the sliding vane of FIGURE 7;

FIGURE 9 is a detailed vertical sectional View taken substantially along line IXIX of FIGURE 2, and illustrating an arrangement for bonding a resilient cap to the rotary piston;

FIGURE 10 is a fragmentary sectional view taken through the axis of a pump illustrating another form of a sliding separator vane; Y

FIGURE 11 is a vertical section view taken through a pump illustrating another form of embodiment of the principles of the invention;

FIGURE 12 is a vertical sectional View taken substantially along line XII-XII of FIGURE 11, and primarily illustrating the lubricant flow path;

FIGURE 13 is a fragmentary sectional view taken substantially along line XIII-XIII of FIGURE 14', illustrating the details of another form of the sliding pivotal separator vane and the pump chamber;

FIGURE 14 is a fragmentary sectional view taken substantially along line XIVXIV of FIGURE 13; and,

FIGURE 15 is a vertical sectional View taken through an embodiment of the invention wherein a plural-stage pump is provided.

As shown on the drawings:

The pump, as illustrated in the embodiment shown at 16 in FIGURES 1, 2 and 3, primarily. includes a casing 17 with a cylindrically shaped pumping chamber 18 therein. Within the pumping chamber is a rotary piston 19 which also may be termed a rotor or a roller. Leading into the side of the pump chamber is an inlet port 21, and leading from the pump chamber is an outlet or discharge port 22. The pump rotor 19 is driven in an oscillating motion around the chamber 18 to force fluid along the outer wall of the chamber from the inlet port 21 through the outlet port 22. Fluid is prevented from leaking from the outlet port to the inlet port by a sliding separator vane 23, mounted in a radial slot 24 in the rotor 19.

The discharged fluid enters a separator chamber 26, which also may be termed an expansion chamber. The separator chamber 26 is separated from the pumping chamber 18 by a separator plate 27.

The pump is well adapted for use as a gas compressor, and lubricant will be carried with the gas into the separator chamber 26 and separated therefrom by a fiinger 28. The pressurized gas leaves through a delivery line 29. The lubricant is recirculated in a manner which will be described.

The mechanism of FIGURES l to 3, in greater detail,

include a casing 17 which has a cylindrically shaped outer wall 17a with a radial end Wall 17b at one side of tliecasing, and an end plate 32 closes the other side of the casing. The end plate has an annular inwardly extending flange 32a which centers it with respect to the casing wall 17a. The end plate is held to the casing, such as by bolts 34 which are turned into threaded bosses 36 on the casing, FIGURE 2. The end plate 32 is provided with an opening 32b in which is secured the condui-t 29 for the discharge of compressed gas from the separator chamber 26.

The end wall 17b of the casing has a tubular extension 17:. which supports bearings for a drive shaft 37 for the pump.

The pump chamber 18 within the casing 17 is defined by an annular or curvate outer wall 38 with adjoining radial side walls 39 and 41. The wall 39 is the inner surface of the end wall 17b of the casing and the wall 41 is the inner surface of the separator plate 27.

The inlet port 21 is shown as being formed through a boss on the side of the casing, and formed with internal threads for the connection of an inlet line. The inlet port 21 leads to a slightly enlarged portion 42 for distribution of the incoming gas in the pumping chamber 18.

An important feature of the invention is the provision of a unique circumferential cap 43 for the rotor 19, and the provision of resilient side walls for the rotor which sealingly engage the inner side walls 39 and 41 of the pumping chamber 18.

The cap 43 includes an outer peripheral portion 44 which is bonded to the outer surface 46 of the rotor 19. The cap includes integral side wall portions 47 and 48, which are bonded to the side surfaces 49 and 51 of the rotor.

The cap is formed of a resilient material which is bonded such as by cementing or vulcanizing to the surfaces 46, 49 and 51 of the rotor, and is formed of a rubber or similar elastomer having characteristics which will withstand the heat of the fluid compressed, and which will not be adversely affected by the pumped fluid or the lubricant.

The resilient facing on the outer surface and especially on the side walls eliminates the need for metal-tometal contact. This obtains a better operating gas seal and prevents fluid lock for minimum gas re-expansion as the pumping chamber closes to zero opening. Under certain conditions of operation, lubricant, such as oil, is gathered ahead of the traveling point of contact between the rotor and the outer wall 38 of the pumping chamber, and as this contact moves to zero position, oil is trapped. This would cause a fluid lock, if the space closed to zero and could not deform. Without the provision of a resilient facing, a space factor would have to be provided so that the pumping chamber did not close to zero, and this would reduce the efficiency of the unit. The high pressure gas left in this space would expand into the gas at suction pressure as the rotor passed the zero position, thus lowering the efficiency of the unit. The oil that is collected in this way is not constant and, therefore, a constant closing space cannot be provided.

This action is illustrated in FIGURE 3, where the resilient cap 43 deforms at 52. The cap strip 43 ends at 53 and 54 at the sides of the vane 23, thus forming a seal between the pumping chamber and the vane, preventing the escape of gas down into the rotor slot 24. The cap also aids in forming a seal between the rotor and the outer wall 38 of the pumping chamber, since the resilient material of the cap is compressed and forced forwardly into the space between the vane 23 and the rotor slot 24, and the space between the vane 23 and the wall 38 of the pumping chamber.

In a modified form, as illustrated in FIGURE 3a, a modified vane 56 is provided with recesses or indentations' 56a and 56b on the side flat surfaces. These recesses receive the ends 53 and 54 of the resilient cap and aid in providing a seal between the vane 56 and the cap, and also aid in holding the vane outwardly in sealing relationship with the wall 38 of the. pumping tomer.

chamber. The cap strip 43 stays on the outer surface of the rotor and functions the same as in the other embodiments, but the ends of the cap strip press into the recesses 56a and 56b only when the rotor is in the position shown and the pressure of the discharging fluid tends to flatten and displace the strip, as shown in FIGURE 3. In this rotor position the ends of the strip will be forced into the recesses by radial pressures on the strip which expand the strip circumferentially and the cap ends 53 and 54 tend to enter the recesses. When the vane slides upwardly out of the rotor, the cap ends leave the recesses.

The rotor 19 includes a rigid central support portion for the resilient cap 43 which includes a hub 58 surrounded by an outwardly extending annular web 59 which carries an outer flange or rim 61. The rim 61 supports the resilient cap 43.

Another form of bonding the cap 43 to the rotor is illustrated in FIGURE 9. In this form, a rotor 62 has an outer rim 63, and the cap has an outer portion 66 with integral inwardly extending side wall portions 67 and 68. The side wall portions have axially inwardly turned flanges 69 and 70. These flanges are received and held in grooves 71 and 72 in the sides of the rotor rim 63 to effectively support and hold the cap in place. The cap further is anchored by a radially inwardly extending enlarged head portion 73, which is received and held in a groove 74 having overhanging side walls 74a and 74b to lock the bead and consequently, the outer portion 66 of the cap to the rotor.

The center portion of the rotor is of necessity of a rigid material to withstand the driving forces of the pump and the pressures as the compressor pump operates. In some instances, however, it may be possible to form the rotor of a unitary section of material with resilient side walls and a resilient outer surface.

The resilient side walls of the cap 43 on the rotor 19 sealingly engage the inner walls 39 and 41 of the pumping chamber. An effective seal is achieved and reduced frictional losses are accomplished. Further, the manufacting tolerances between the rotor and the pumping chamber are considerably reduced, thereby reducing the cost of production of the compressor pump.

The rotor is substantially free floating between the walls 39 and 41 of the pumping chamber, since the web 59 is provided with a pressure equalizing hole 76. This equalizes the gas pressures which may be built up and also permits transfer of lubricant across the rotor.

The sliding pivoting vane 23 is slidingly contained in the axially extending outwardly opening slot 24 in the rotor 19. The vane is in sealing relationship with the sides of the rotor slot 24, and with the outer wall 38 of the pumping chamber. The vane is held in its pivotal position, and in the outwardly radial sealing relationship to the wall 38 by axially extending lateral cars 76 and 77 at the sides of the flat vane 23. The vane 76 is received in the positioning recess 78 in the separator plate 27. The car 77 is received in the positioning recess 79 formed in the side Wall 39 of the pumping chamber. These pivoting cars can have a diameter different from the vane thickness and also can be located in any position down the length of the vane. The gas pressure at the base of the slot tends to hold the vane in the correct operating position. A compression spring 81 in a slot 83 in the vane, bottoming at 82 in the rotor slot may also be provided.

The vane 23 prevents leakage of fluid from the outlet port 22 to the inlet port 21 and is located between these ports. The vane seals against the side walls 39 and 41 of the pumping chamber, and against the outer wall 38 and is provided with a resilient sealing strip 84, FIGURES 7 and 8, which is bonded in a groove 86 extending around the side and top edges of the vane. This strip 84 is of a resilient material such as rubber or other suitable elas- In some circumstances, the vane itself may be formedof an elastomeric material, such as rubber or plas tic. The hardness will vary with the pressure of the fluid and the type of fluid and diameter of pump. With a larger diameter and more flow, it is necessary to use a harder material.

In some circumstances, it will be advantageous to coat the side and top edges of the vane with rubber, such as by dipping or other suitable coating process. The structure illustrated in detail in FIGURES 7 and 8, or the alternative structures referred to above, will provide effective seals and will reduce the wearing friction between the vane and walls of the pumping chamber.

Since the gas pressure tends to hold the vane radially outwardly in the correct operating position, it can operate with one ear or one extension, as is illustrated in the form of a pump 88 illustrated in FIGURE10, In this pump, a casing 91 has a pumping chamber '32 therein with side walls 93 and 94, and a rotor 39 in the pumping chamber. The rotor is rotatably journalled to be driven by a shaft 99, and an inlet port is located at 101 to lead'into the pumping chamber 92. Gas is discharged into a separator chamber 98 past a ported separator plate 97.

A radially extending pivoted vane 102: sealingly engages an outer wall 96 of the pumping chamber 92 and is located in a slot 103 in the rotor 89. A single positioning ear 104 extends into a' positioning recess 106 in the side wall 9 3 of the pumping chamber.

The outer wall 38 of the pumping chamber 36 is provided with. an axially extending cylindrically shaped groove 108, FIGURES 2 and 3. The outer end 109 of the vane 23 is rounded with substantially the same curvature to sealingly fit into the groove 108. The groove is arcuately shaped with the are being swung from the tilting center 111 of the vane. This tilting center 1111 can be any place along the length of the vane, and to minimize relative motion between the vane and the recess or groove 108, the tilting center is placed as close as possible to the groove.

As'state'd, the arc of the groove 108is struck from the tilting center 111, and must be less than a 180 or semicylindrical recess, to provide edge clearance with tilting movement of the vane. In some instances, edge clearance may be provided by. relieving the sides of the recess.

Another form of improving the seal of the separator vane is illustrated in the embodiment shown by a pump 112 in FIGURES 11 and 12. This pump mechanism includes a casing 113, with a pumping chamber 114 therein defined by a curvate outer wall 115 and side walls116 and 117. A rotor 118 is located within the pumping chamber 114. A pivotal sliding vane 119 is located in a radial slot 120 in the rotor 118'and is in sealing engagement with arecess 110 with the'outer wall 115 of the pumping chamber. In this form, the vane 119 is positioned by a single support pin 121 mounted in" an axial bored hole 122 in'the vane, and mounted in a corresponding axially extending-hole 123 in the casing 113 opening from the side wall 117 of thepumping chamber.

A pressurized flow of lubricating fluid lubricates the pm 121 and also provides a sealfor the vane 119. Lubricating oil is separated from the pumped gas in the expansion or separator chamber 126, and collected at the bottom 127 of the chamber. A separator plate 204 between the expansion chamber126'andthe pumping chamber 114 is provided with a lubricating oil conduit 1'24, which-leads from the oil sump location127up through the plate 116, to register with the lubricating passageway 128- extending through the vane and opening into the hole 122 containingthe positioning pin 121. This lubricates the pinfor long wear be'tween the pin and the vane. The pressurized oil is also forced into an edge oil groove 129 extending on both sides of the vane and across the top of the vane 119. This groove contains oil under pressure to provide a' good gas seal. The length, width and depth of the oil groove is-kept-to a minimum size consistent with good sealing requirements. The expansion chamber 126 is,- of

course, under pressure receiving g'as discharged from the pump and will force pressurized oil up through the pas sage 124 into the groove 129. Thus, oil will fill the groove at a pressure equal or greater than the gas pressure, at adjacent faces ofthe vane. Therefore, gas will not leak across the oil stream. However, a slight leakage of oil will take place. It is important that the volume of oil in the grooves be kept to a minimum consistent with its function.

Where the compressor is used in a refrigeration system utilizinga gas such as Freon, the lubricating oil will absorb the Freon, and the gas will expand from the oil, and will have to be recompressed. The oil will leak into the pumping chamber to be returned with the gas to the separator chamber 126, and some oil will leak past the sides of the rotor 118 into an oil accumulation chamber 131 which is formed between the web 132 of the rotor and the wall 117 of the pumping chamber. This oil will recirculate through the pump in a manner which will later be described.

Another form of pivotal vane to obtain improved sealing between the vane and pumping chamber wall is shown in FIGURES 13 and 14. A pump 133 is shown with a casing 134 having a pump chamber 137 therein, withan outer curvate wall 136. A rotor 138 is mounted within the chamber and an inlet port 140leads into the pumping chamber 137. A pivotal vane 139 is carried in a slot 146 in the rotor 138. At the outer end of the vane is a groove or recess 141 which facesa corresponding groove or recess 144 in the outer wall 136 of the pumping chamber 137. Seated in grooves 141 and 144 is a sealing pin 143. The sealing pin has upper and lower cylindrically shaped surfaces, and may be completely cylindrical in shape. The pin extends across the top of the vane 139 between the side wall 148 of the pumping chamber and a separator plate 142, which forms the other side'of' the pumping chamber. The pin provides a low friction, low wear support for the vane and provides an efiective seal between the inlet and outlet ports which communicate withthe pumping chamber.

The outlet port 22 from the pumping chamber 18-, FIGURES 1, 2 and 3, is provided with check valve means whichprevent thebaek flow of compressed gas; The separator plate 27 is provided with an oblong recess 147' and the outlet port 22 is located within this recess. A cantilever spring check valve plate 148 is secured at one side of the outlet port within the recess 147, and'fl'exes to per' mit discharge flow of compressed gas.

For maximum performance and efiiciency, compressed gas from the pumping chamber must be able tofiow from thepumping chamber until zero position'of the rotor, when the discharge space inthe chamber is at zero; With a circular opening such as illustrated at 22, it is not possible to have the discharge port extend conveniently into the area closely adjacent the vane 23, and the outer wall 38 of the pumping chamber for final discharge. The pump 151, illustrated in FIGURE 4, shows a casing 152 having a pump chamber 154" therein with a rotor 1 53 within the chamber. The casing has an outer curvate wall 156, and a vane 157 within a slot in the rotor sealingly engages the wall 156. A plurality of small discharge or outlet ports 159, 161, 162 and 166 are arranged in a radially extending row, and extend through a separator plate 158 adjacent the vane 157. A check valve member 164 is attached to the separator plate 158 and is'provided with port closing spring fingers 164a, 164b, 1640' and 164d, which extend over the ports and prevent the back flow of gas. Theplurality of ports accommodate the discharge of compressed gas from the pump 151 throughout the-discharge stroke of the rotor 153, and accommodate the flow of gas to the final zero discharge position of the rotor. The arrangement and size of the ports make it possible to extend the ports to critical positions to accommodate the final flow of gas as the rotor reaches zero discharge position.- In some instances, a continuous elongated port through the separator plate 158, beside the vane, would serve the required purposes. For a commercial pump, a series of ports is more practical, inasmuch as an inexpensive leaf valve plate, such as 164 is successfully operative with a plurality of port closing fingers, and is not practical for sealing an elongated port. Furthermore, the ports can successively close, as the rotor moves toward zero position, reducing the space between the rotor and the outer wall 156 of the pumping chamber.

In the pump 166 of FIGURE 5, a casing 167 is provided with a pump chamber 169 therein, and a rotor 168 mounted within the pump chamber. A separator vane 172 extends in a slot in the rotor to sealingly engage an outer wall 171 of the pumping chamber 169. A plurality of gas outlet ports 173, 174, 176 and 177 are arranged in a circumferential pattern to extend through a separator plate 178. The small ports are arranged so that the discharge of compressed gas can be handled as the rotor 168 rotates toward zero discharge position. A flow return check valve similar to the plate 164 shown in the pump of FIGURE 4, is provided to cover the ports 173, 174, 176 and 177.

As the compressed gas with entrained oil enters the separator or expansion chamber 26, the oil is separated from the gas by a flinger disc 28, FIGURES l and 6. The fiinger disc is mounted to be driven in oscillating rotation at the end of an offset extension 181 of the drive shaft 37. This offset or eccentric extension also rotatably carries the pump rotor 23, and with rotation of the shaft 37, the rotor will be driven in an oscillating motion. Simultaneously, the flinger disc 28 will be driven in rotation to separate the lubricating oil from the gas, which passes out through the conduit 29. To counterbalance the flinger disc 28 and provide for dynamic stability at high speed rotation of the pump,and also to act as separator members, the disc 28 carries vanes, such as illustrated at 184, 185, 186, 187, and 188 in FIGURE 6. These vanes extend radially outwardly from a hub 182 of the disc which is provided with a key 183 for locking the disc to the offset shaft portion 181. As will be observed in FIG- URE 6, the vanes are shaped so that vane 184, which is at the offset or outside side of the disc 28 is thinner and of lighter weight than the vane 188 which is at the inside side of the disc. The vanes grow progressively larger and heavier with vanes 185, 186, 187 and 188 progressing in size, and the vanes at the other side of the disc progressing in size in a similar manner. This counterbalances the weight of the disc and provides for dynamic stability.

The separator plate 27 which separates the separator chamber 26 from the pumping chamber 18, is urged toward a small shoulder 189 which limits its movement toward the pumping chamber by a wave spring 191. The wave spring 191 is backed by the flange 32a on the casing plate 32, and holds the plate in place. The plate has a central opening 27a through which extends the offset shaft extension 181.

The drive shaft 37 is supported in bearing bushings 192 and 193 within the tubular extension 170 of the casing. An oil seal 194 is provided at the end of the casing extension. The shaft is driven by a pulley 196 or the like connected to the shaft such as by a cross pin 197.

The bearings 192 and 193 and shaft 37 are lubricated by a first oil conduit 198 which opens from the base of the separator chamber 26. The conduit 198 leads to the bearings 192 and 193, and oil flows through the conduit to lubricate the bearings and flows inwardly from the seal 194 along the shaft 37 to flow into an oil accumulation chamber 199. This chamber is defined by the web 59 of the rotor and the side wall 39 of the pumping chamber. Oil is removed from the lubricating chamber by a second oil conduit 201, which opens at an aspirator opening 282 in the intake port 21. The How of gas through the intake port forms a suction to draw oil through the second conduit 20 1 by an aspirating action. The oil mixes with the gas and lubricates the pump rotor and pump vane. The position of the opening 203 at the lower end of the conduit 201 determines the level at which the oil will remain in the accumulator chamber 199.

This automatic oil circulation arrangement is used with the pump 16 which embodies a vane 23 having a rubber or resilient sealing edge, and not requiring direct lubrication. In the form of the pump 112 illustrated in FIG- URES 11 and 12, an oil pressure seal is used, and the vane receives direct lubrication.

As previously described, the oil flows up through the conduit 124 which extends through a separator plate 204 to meet the lubricating passageway 128 and the sealing passageway 129 in the vane. The sealing plate 116 may be locked against accidental rotation to insure alignment of the passages by a radially extending locking screw 206 extending into a slot 207 at the edge of the plate 204. If desired, a conduit separate from the plate may be used to replace the conduit 124.

The oil escaping from the groove 129 flows down past the vanes and along the walls of the pump chamber toward the center of the rotor 118, and fills the oil accumulator chamber 131. This oil lubricates roller bearings 208 and 209 supporting a drive shaft 211. The drive shaft 211 has an offset portion 212 for driving the rotor and for driving a flinger 213. The shaft is driven by a pulley 214 or the like. An oil seal 216 is located at the end of a casing extension 217 to prevent the escape of oil along the shaft 211.

Oil is removed from the accumulator chamber 131 through an oil conduit 218. The conduit opens into the accumulator chamber at 219 to determine the level of the oil in the chamber. Oil is drawn through the conduit 218 by the aspirating action of gas taken into the pump through an inlet port 222, and an upper end 221 of the oil conduit opens into the side wall of the inlet port 222. This insures continual circulation of the oil, since the oil will then he entrained with the gas as it is compressed to flow through the pump and again be separated from the gas in the separator chamber 126.

The features of the invention are well adapted to utilization in a multi-stage pump, as illustrated at 224 in FIG- URE 15.

The pump includes a casing 226 with a radial end wall 229 and outer wall 231. Secured to the outer wall 231 is an end plate 227. The casing has a cylindrical inner surface 228 and a first circulator separator plate 232 is located within the pump casing to separate a first pump chamber 233 and a second pump chamber 234. A separator plate 236 forms one side wall of the second pump chamber 234. Within the first and second pump chambers 233 and 234 are rotary pump pistons or rotors 237 and 238. The rotors are driven by a drive shaft 239 journalled in a casing extension 241. The drive shaft 239 has an eccentric extension portion 242 which rotatably carries the pump rotors 237 and 238.

An inlet port 243 leads through the wall of the casing 226 into the first pump chamber 233. An outlet port 244 leads from the pump chamber to a discharge conduit 246 which leads to an inlet port 247 leading into the second pump chamber 234. The second pump chamber discharges through an outlet port 248 through the separator plate 236. A return-preventing, fiat check valve covers the outlet port 248. The outlet port discharges into separator chamber 251 and pressurized gas is delivered through a delivery conduit 252 leading through the end plate 227 of the casing. Lubricating oil is separated from the compressed gas in the separator chamber by a flinger 253 which is connected to the offset portion 242 of the drive shaft. An annularly extending wave spring bottoms against a flange on the casing plate 227 and bears against the separator plate 236. A pin 256 through the casing wall extends into a slot 257 of the separator plate to prevent accidental rotation of the plate.

aosmze Another; pin 258 extends-through the casing wall into-a slot 258a in the plate 232 to prevent rotation.

Oil separated from the compressed gas in the separator chamber 251 flows tothe bottom of the chamber, and is forced out through a lubricatingpassageway 259 and the passageway connects to a conduit 261 to lubricate bearings 262 supporting the rotor shaft. 239.: The oil flows inwardly to an oil accumulator chamber 263. A second lubricating conduit 264 has a lower end 266 which draws from the accumulator chamber 263 and determines the level therein. Suction in the second lubricating conduit 264is provided by the outlet 267 opening into the side of the inlet port 243 for the first pump chamber, thereby providing an aspirating pumping action. The lubricant will then flow through the first pump chamber 233, and

be entrained with the compressed gas flowing through the gas conduit 246 and will flow into the second pump chamber 234 to be returned tothe separator chamber 251 for automatic recirculation of. the lubricant. I Each of the rotors 237 and 238 carry a pivotal vane 268 and2 69, respectively. Each of the vanes is provided with pivoting ears with cars 26% and 26% providedfor the vane 269, and ears 268 a. and 26812 for the vane 268. Positioning recesses 273 and- 274 areprovided for the vane 269, and receive the ears 269a and 26%. Positioning recesses 278 and 279 are provided for the vane 268 andreceive the ears 268a and 268b; Coilsprings 281 and 282 urge the vanes 268 and 269, respectively, outwardly into sealing relationship with the outerwalls of. thepump chambers 233 and 234 and, thus aid the pressurizedgas in the slots in holding the vanes outwardly. The vanes are provided with side and outer rubber edges 286 and 287 to provide a good sealing and sliding relationship with the walls of the pumping chambers.

The rotors move in good sealing and sliding relationship with the side Walls of the chambers, being provided with rubber caps 288 and 289 which have inwardly extending sides to form the sealing sides for the rotor and have outwardly facing surfaces over the rigid material of the rotors in order that the units may have zero delivery volumes without building up excessive pressures, and bursting the parts. The rotors float within the chambers and axial pressure relief openings 291 and 292 are provided through the rotors to prevent building up unequal pressures on either side of the rotors.

In operation, as may be illustrated by the embodiment of FIGURES 1, 2 and 3, the drive pulley 196 is driven in rotation to drive the shaft 37. The rotor 19, carried on the eccentric shaft portion 181 is moved in an oscillating motion around the pump chamber 18 to force gas along the outer wall 38 of the pump chamber from the inlet port 21 to the outlet port 22. The rubber cap 43, which is bonded to the rotor, is shaped to form an effective sliding seal between the side walls 39 and 41 of the pumping chamber, and the sides 47 and 48 of the rotor cap. The vane 23 meets the outer wall '38 of the pumping chamber in sealing relationship, and is provided with a resilient edge 84 for this purpose. As the compressed gas flows into the separator chamber 26, the flinger 28 separates the lubricating oil which has become entrained in the gas. The gas flows out through the conduit 29, and the lubricant flows through the first lubricating conduit 198 to the bearings 192 and 193 and into an oil accumulator chamber 199. Oil is drawn from the accumulator chamber to the second lubricating conduit 201, benig drawn through the conduit by the aspirating action of the conduit opening at 202 into the intake 21 for the pump.

Thus, it will be seen that I have provided an improved pumping mechanism which meets the objectives and advantages hereinbefore set forth. The mechanism is capable of operation with improved efliciency over structures heretofore used. Further, the parts of the pump can be constructed for effective reliable operation of the pump without observing the close. manufacturing tolerances which were heretofore necessary.

While the pump, as herein described, is used for gas compression, it will be understood that it is well adapted to other uses. The pump canreadily be used as a vacuum pump by connecting the inlet port to" a chamber to be evacuated and discharging into atmosphere through the outlet port. While well adapted touse' as a refrigerator compressor, it may be used for other compression operations. Gases of various types may be handled, such as ammonia, nitrogen, helium and hydrogen. The pump may also be used as a highpressure pump, or, for example, can be usedas anair compressor for automotive suspension systems.

I have, in the drawings and specification, presented. a detailed disclosure of the preferred embodiments of my invention, and it is to be understoodthat I do not intend to limit the invention to the specific form disclosed, but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principlestau'ght by my invention.

I claim as my invention:

1. A fluid pump comprising a casin'g with a pump cham ber therein having an outer wall and adjoining side walls, a rotary piston within said chamber, means defining an inlet port and an outlet port in communication with said chamber, means connected to said piston for drivingthe piston in an oscillating motion to force fluid along the outer wall'of the chamber from the inlet port to the outlet port, means defining a radial slot extending inwardly from theoutef edge of the piston and opening axially from the piston, a flat sliding vane in said slot, means for holding the vane in a radial sealing relationship with the outer wall of the pump chamber, a piston cap strip of resilient material extending around the outer surface of the piston for sealingly engaging the outer wall of the chamber with oscillating movement of the piston, and means defining recesses in the circumferentially facingsurfaces of said vane at the outer end of the vane for receiving the ends of said cap strip in sealing relationship to the vane when the vane is slid into said slot a maximum distance.

2. A fluid pump comprising a casing having a cylindrical-shaped pumping chamber therein with an inwardly facing circumferential wall, a cylindrically shaped rotary piston within said pumping chamber, means defining inlet and outlet ports in said casing communicating with said pumping chamber, a radially outwardly extending axial slot in said piston positioned between the inlet and outlet ports, a separator vane slidably positioned in said slot and having an axially extending first groove in the radial outer end, means defining a second groove in the radially inwardly facing Wall of the chamber, means urging said vane outwardly toward the outer wall of said pumping chamber, an axially extending free pin having cylindrical surfaces facing radially inwardly toward the vane and facing radially outwardly toward the wall of the chamber and seated in said grooves, said cylindrical surfaces in rolling and sealing engagement with the grooves of the vane and chamber wall respectively with the pin held therebetween, and means connected to said piston for driving the piston in an oscillating motion to force fluid from the inlet port to the outlet port.

3. A casing defining a pump chamber therein having an outer wall and adjoining side walls with inlet and outlet ports in said casing communicating with said chamber, a rotor positioned within said chamber, means for driving the rotor in an oscillating motion to force fluid from the inlet port to the outlet port along said outer wall, means defining a radially opening slot in said rotor, at flat separating vane slidably positioned in said slot between said ports, an outwardly facing open sealing groove extending along the edge of the vane and facing outwardly toward said outer wall and said side walls, and a pressure fluid conduit connected to said sealing groove for delivering a pressurized sealing fluid thereto so that sealing fluid fills the groove and contacts the outer and side walls of the chamber which are faced by the open groove to prevent leakage of pumped fluid past the vane.

4. A casing defining a pump chamber therein having an outer wall and adjoining side walls with inlet and outlet ports in said casing communicating with said chamber, a rotor positioned within said chamber, means for driving the rotor in an oscillating motion to force fluid from the inlet port to the outlet port along said outer wall, means defining a radially opening slot in said rotor, a fiat separating vane slidingly positioned in said slot between said ports, an outwardly facing open sealing groove extending along the axial outer side and radial outer top edges of the vane and facing the outer wall and side walls of the chamber, a separator chamber connected to said outlet port to receive pumped fluid and separate entrained lubricant, and a lubricating fluid conduit connected to said separator chamber to conduct lubricant therefrom and to said sealing groove to deliver lubricant to said sealing groove at outlet port pressure and fill the space between said groove and outer and side walls and prevent leakage of pumped fluid past the vane.

References Cited in the file of this patent UNITED STATES PATENTS 711,092 Bates Oct. 14, 1902 1,416,695 Dennedy May 23, 1922 1,502,470 Hart July 22, 1924 1,602,301 Guttner Oct. 5, 1926 1,628,888 Klinge May 17, 1927 1,799,287 Daubenmeyer Apr. 7, 1931 12 Ericson Aug. 15, Zimmerer Aug. 22, Teves Dec. 18, Badger Oct. 22, Bingham May 12, Steinmann Aug. 11, Kosian June 22, Heinz May 17, Hull et al. Nov. 8, Friedell et al. Jan. 7, Fraser June 17, Woods et al. Jan. 5, Barker Oct. 19, Balogh Feb. 1, Kiekhaefer Jan. 3, Seastrom Feb. 28, Gordinier Dec. 18, Makaroff et al. June 30, Preiss Sept. 14, Rochford et a1 Feb. 21, Smith Aug. 7, H011 Apr. 30, Shafer June 11, Makaroff et a1 July 23, Ludwig et al. Sept. 1,

FOREIGN PATENTS Great Britain Mar. 18, Australia Jan. 20, Italy May 19, France May 22, 

2. A FLUID PUMP COMPRISING A CASING HAVING A CYLINDRICAL-SHAPED PUMPING CHAMBER THEREIN WITH AN INWARDLY FACING CIRCUMFERENTIAL WALL, A CYLINDRICALLY SHAPED ROTARY PISTON WITHIN SAID PUMPING CHAMBER, MEANS DEFINING INLET AND OUTLET PORTS IN SAID CASING COMMUNICATING WITH SAID PUMPING CHAMBER, A RADIALLY OUTWARDLY EXTENDING AXIAL SLOT IN SAID PISTON POSITIONED BETWEEN THE INLET AND OUTLET PORTS, A SEPARATOR VANE SLIDABLY POSITIONED IN SAID SLOT AND HAVING AN AXIALLY EXTENDING FIRST GROOVE IN THE RADIAL OUTER END, MEANS DEFINING A SECOND GROOVE IN THE RADIALLY INWARDLY FACING WALL OF THE CHAMBER, MEANS URGING SAID VANE OUTWARDLY TOWARD THE OUTER WALL OF SAID PUMPING CHAMBER, AN AXIALLY EXTENDING FREE PIN HAVING CYLINDRICAL SURFACES FACING RADIALLY INWARDLY TOWARD THE VANE AND FACING RADIALLY OUTWARDLY TOWARD THE WALL OF THE CHAMBER AND SEATED IN SAID GROOVES, SAID CYLINDRICAL SURFACES IN ROLLING AND SEALING ENGAGEMENT WITH THE GROOVES OF THE VANE AND CHAMBER WALL RESPECTIVELY WITH THE PIN HELD THEREBETWEEN, AND MEANS CONNECTED TO SAID PISTON FOR DRIVING THE PISTON IN AN OSCILLATING MOTION TO FORCE FLUID FROM THE INLET PORT TO THE OUTLET PORT. 